1. Field of the Invention
This invention relates to a process for the pretreatment of soiled fabrics. By the application of a paste containing active substances to the soiled fabrics and subsequent washing of the fabrics thus pretreated in a wash liquor, the cleaning of the fabrics is distinctly improved over non-pretreated fabrics.
2. Discussion of Related Art
In the washing of fabrics, a wash liquor is generally heated to an elevated temperature compared with room temperature. This measure enhances the detergency of the detergents used, in some cases to a considerable extend. However, the heating of the wash liquor and of the fabrics involves a high consumption of energy during the washing process. Since, in addition, many fabrics, particularly fabrics of wool or synthetic fibers, cannot be washed at elevated temperature for various reasons, attempts have repeatedly been made to obtain good washing results at low washing temperatures. In many cases, however, the effect of commercial detergents at low washing temperatures is reduced or even weakened to such an extent that the fabrics cannot be satisfactorily cleaned by washing. Through various measures, attempts have been made to improve detergency even at low washing temperatures. In one such effort to solve this problem, German patent application No. 27 44 642 describes a detergent additive which contains an organic bleach activator in water-releasable combination with a non-particulate substrate. A further improvement in the detergency of detergents is provided by an additive which, according to German patent application No. 28 57 153, contains in addition to a bleach activator a combination of an alkoxylated nonionic surfactant and a cationic surfactant with one radical containing from 8 to 20 carbon atoms and, for the rest, short chain radicals containing from 1 to 4 carbon atoms on a substrate. However, one disadvantage of this additive is that, on removing the additive from its pack and adding it to the detergent solution, the user comes into contact with the active substances which, apart from an occasionally unpleasant feeling, can lead to skin irritation. Another disadvantage of the additive in question is that, after washing, the water-insoluble substrate has to be recovered from the washed fabrics. To avoid the above-mentioned disadvantages, German patent application No. 34 15 880 describes a washing additive consisting of a mixture of several detergent ingredients accommodated in a bag based on polyvinylalcohol which is soluble in detergent solutions. The mixture of several detergent ingredients accommodated in a bag according to the teaching of this patent application is in the form of a paste which is adjusted by the addition thereto of an antigel agent and certain viscosity regulators to such a viscosity that it dissolves quickly and completely in the still cold detergent solution. Another solution to the above-mentioned problems is described in German patent application No. 28 57 157. According to the teaching of this patent application, the detergents contain certain nonionic and certain cationic surface-active compounds in a certain ratio to one another. The described preparations may be formulated as pastes and may also be used for the pretreatment of soiled fabrics. However, the patent application in question does not suggest what particular measures have to be taken in regard to the composition of pastes that are readily soluble in cold wash liquors, or that the application of pastes having a certain composition to soiled pieces of fabrics leads to particularly good washing results.